Pilot means for die set



May 1, 1962 c. H. MOVEY PILOT MEANS FOR DIE SET 2 Sheets-Sheet 1 Filed Aug. 16, 1957 FIG. 3

- INVENTOR. CLARENCE H. McVEY ATTORNEY FIG. 5 Q /2 15 FIG. 4

C. H. M VEY May 1, 1962 PILOT MEANS FOR DIE SET 2 Sheets-Sheet 2 Filed Aug. 16, 1957 Pllll FIG.8 FIG. 9

INVENTOR. CLARENCE H. MCVEY ATTORNEY FIG. IO

United States Paten t O 3,032,378 PILOT MEANS FOR DIE SET Clarence H. McVey, 54 Holman St., Laconia, N.H. Filed Aug. 16, 1957, Ser. No. 678,692 2 Claims. (Cl. 308-4) This invention relates to improvements in die sets of the type comprising two cooperating parts, a punch carrying plate and a die carrying plate and more particularly to pilot means for facilitating the insertion of the guide posts on one plate with the mating bushings on the complementary plate.

Conventional die sets present difficulties in assembling and disassembling the co-operating parts due to the requirements for close tolerance relationship and absolute axial alignment of the guide posts with the bores of their companion bushings. The greatest diificulty in assembling the punch carrying plate with the die carrying plate occurs during the initial insertion of the guide posts into the bores of their mating bushings to effect an extent of engagement there between at least equal to the diameter of the post.

It has been a common practice to employ a hammer with a lead, leather or fiber head for initially forcing the guide post into their mating bushings. On the other hand, a prybar is sometimes used to separate the punch carrying plate from the die carrying plate. Such methods often result in damage to the punch or die besides being time consuming and inconvenient for the operator. It is therefore an object of the present invention to provide pilot means co-operating between the guide posts and their mating bushings to effect easy and convenient engagement of the guide posts with their mating bushings.

The present invention is an adjunct to my prior invention, application Serial Number 600,980 filed July 30, 1956, for Pilot Means for Die Set, and now abandoned.

The present invention is particularly useful with four post die sets Where the posts are of the larger diameters employed by the trade but it has application to two post die sets and to small diameter posts in both two and four post die sets. My prior invention is particularly useful to two and four post die sets where the posts are of the smaller diameters employed by the trade.

Another object, which both inventions have in commom, is to provide pilot means between the guide posts and their mating bushing for effecting, axial alignment there between by slightly tilting the punch carrying plate relatively to the die carrying plate.

And still another object, which both inventions have in common, is to provide a die set with posts of different lengths so that the post of longest extent may first be entered into its mating bushing to accurately align each of the several posts with the bore of its mating bushing.

A further object of the present invention is to provide an improved type of guide post for die sets with pilot means formed by backing-off the free end of the post to form a land, having a diameter slightly smaller than the diameter of the post, and an angular and/or circular recess adjacent said land and terminating in an aligning angle consistent with the diameter of the post, so that the punch carrying plate may be relatively tilted (without binding) to the die carrying plate to bring the posts and their mating bores into axial alignment to provide absolute parallelism between the punch carrying plate and the die carrying plate.

And still another object of the present invention is to provide an improved type of bushing for die sets with pilot means formed in the bushing, so that the punch carrying plate may be relatively tilted (without binding) to the die carrying plate to bring the bushings and their mating posts into axial alignment to provide absolute par- "ice allelism between the punch carrying plate and the die carrying plate.

And still a further object of the present invention is to provide a pilot on a post or in a bushing of a die set which is of very short length in extent on the end of a post or in the end of the bore of a bushing.

Other objects of the present invention Will become apparent in part and be pointed out in part in the following specification and claims.

Referring to the accompanying drawings wherein similar characters of reference refer to like parts:

FIGURE 1 is a perspective view of a four post die set incorporating the pilot means of the present invention as applied to the guide posts thereof.

FIGURE 2 is a fragmentary sectional view showing the structural form of the pilot means on the guide posts.

FIGURE 3 is a fragmentary side elevational view of a guide post and a fragmentary sectional view of its co-operating bushing showing the post at an angle of tilt as it initially enters the bushing prior to the axial alignment of the post with the bushing.

FIGURE 4 is a fragmentary side elevational view of the guide post provided with the pilot means.

FIGURE 5 is a plan view of FIGURE 4.

FIGURE 6 is a side elevational view of the co-operating parts of a die set illustrating guide posts of varying lengths with the pilot means shown on a post and alternately on a bushing.

FIGURE 7 is a fragmentary sectional view showing the present pilot means applied to a bushing. v

FIGURE 8 is a fragmentary view of the end of a guide post showing a modifiedform of pilot means.

FIGURE 9 is a fragmentary view of the end of a guide post showing still another modified form of'pilot means.

FIGURE 10 is a fragmentary side elevational View of the pilot means on the end of a guide post.

Referring to the drawings; the guide post 11 is provided on one end with a pilot means which consists of a lead surface 12, a narrow land 14, a clearance angle 16, a groove 19 and an aligning angle '15.

The following dimensions are provided, not as controlling, but to provide some knowledge of the size of the pilot means and ratio of the dimensions of the interrelated parts. See FIGURES 4 and 10.

Where the diameter (dimension E) of the guide post 11 is between three-quarters of an inch and one and threequarter inches, the diameter (dimension A) of land 14 is two thousandths of an inch less than dimension E. The width of narrow land 14, dimension B, is between fifteen and thirty-one thousandths of an inch. The diameter of groove 19, dimension D, is ten to fifteen thousandths of an inch less than the diameter of post 11, dimension E. Dimension C is approximately one-eighth of an inch. Angles F and G are each sixty degrees. Dimension H may be between two and ten thousandths of an inch. Dimension I is three-sixteenths of an inch.

Where the diameter (dimension E) of the guide post 11 is between two and two and three quarter inches, the diameter (dimension A) of land 14 is three thousandths of an inch less than dimension E. Narrow land 14, dimension B is between thirty-one thousandths of an inch and sixty-two thousandths of an inch. The diameter of groove 19, dimension D, is ten to fifteen thousandths of an inch less than the diameter of post 11, dimension E. Dimension C is approximately three sixteenths of an inch. Angles P and G are both sixty degrees. Dimension H is between two and ten thousandths of an inch. Dimension I is approximately one quarter of an inch.

Where the diameter (dimension E) of the guide post 11 is between three and four inches, the diameter (dimension A) of land 14 is four thousandths of an inch less, dimension E. Narrow land 14, dimension B is bedestroying part of that length in a pilot.

tween sixty-two and ninety-three thousandths of an inch. The diameter of groove 19, dimension D, is ten to fifteen thousandths of an inch less than the diameter of post 11, dimension E. Dimension C is approximately one-quarter of an inch. Angles F and G are each sixty degrees. Dimension H is between two and ten thousandths of an inch. Dimension I is three eighths of an inch.

Dimension H is extremely small and may be a broken edge which is the practical effect of the dimensions given in all three examples.

The angle of tilt (see FIGURE 3, dimension J) or axial alignment angle of the guide post with the axial alignment of the bushing is contemplated to be limited.

The contour of the pilot as shown in FIGURES 2, 3, 4, 8, 9 and 10 is to provide a land 14 which is less than one eighth of an inch wide and which may be as narrow as a circular point of contact on a post or in a bushing. The land 14 is the point of contact which axially aligns the post with the bushing. The groove 19 is a clearance area behind, below or beneath the land 14. Guide posts 11 are fixed in either the upper plate 20 or the lower plate 21. In FIGURE 1 the guide posts 11 are fixed in lower plate 21. Bushings 22 are fixed in upper plate 21.

In practice the length of the posts 11 are limited due to the limitation of the heighth of the ram in a punch press. With the many presses in operation imposing a length limit on the posts of a die set, it is imperative to maintain the full effective length of the post without I The length of pilot on the post must therefore be extremely small to be commercially useful.

In the modified form of land 14A shown in FIGURE 8; the land is relatively wide and is provided with a di- 'ameter, smaller than the diameter of the guide post 11A. v In the modified form of land 143 shown in FIGURE 9; the land is a circular point of contact. The diameter of the land is illustrated as being slightly smaller in diameter than the diameter of the guide post 11B. In this form the diameter of the land 1413 may be equal to but not greater than the diameter of guide post 11B. This point of contact land 11B provides a smoother sliding or engaging action with the bore of the bushing than does the wider widthed lands l4 'and 14A.

Aligning angle B is preferably very shallow. The

angle 12C of lead surface 12B is provided to create the point of contact for land 14B in conjunction with clearance angle 16B. This modified form provides manufacturing expediencies in the form of easy grinding of the lead surface 12B, clearance angle 16B and aligning angle 15B. 7 When guide posts 11 are in parallel alignment with their respective mating bushings they are also in slide fit engagement with a tolerance of between two and three ten thousandths of an inch. Such close tolerances eliminate lateral movement between guide post and bushing. The small tolerances also make it diificult for the guide post to initially enter the bushing. Especially is this condition prevalent when four posts fixed to a plate are placed in position to initially enter four bushings fixed in another plate.

FIGURE 7 illustrates the pilot feature in the bushing 22 rather than on the end of guide post 11. The component parts are indicated as follows: Lead surface 12D, narrow land 14D, clearance angle 16D, groove 19D and aligning angle 15D. The function of the mating of the guide post 11 with bushing 22 is the same whether the pilot is located on the guide post or in the bushing.

,In FIGURE 3 reference character 1 refers to the degree of tilt between the axis 4% of guide post 11 and the axis 41 of bushing 22. This angle is limited and is controlled by aligning angle 15.

Having shown and described preferred embodiments of the present invention, by Way of example, but realizing that structural changes can be made and other examples given without departing from either the spirit or the scope of the present invention.

What I claim is:

1. A die set comprising two cooperating planar surface plates adapted to receive die members on complemen tary co-acting surfaces thereof, a plurality of cylindrical guide posts having a body portion and a projecting end portion fixed at substantially opposite edges in one of said plates, a plurality of mating bushings provided at substantially opposite edges in the other of said plates, each mating bushing having a bore with the walls defining the bore at their juncture with the surface of the plate forming a relatively sharp edge, each of said guide posts removably engaging the bore of a mating bushing, each of said guide posts having a pilot portion formed on said projecting end and having an over-all diameter less than that of said body portion, said pilot portion being formed by a radially inwardly cone portion sloping in the direction of said projecting end and terminating at one end in an annular groove, said groove being of a diameter less than that of the body portion to define a valley portion, a land portion extending radially outwardly and forming the other side of the valley portion and being of a diameter at its largest extent less than that of said body portion, said land portion terminating in a radially inwardly second cone portion sloping in the direction of said projecting end and terminating said pilot portion to define a truncated cone portion, said posts and bushings, upon simultaneous engagement and being misaligned in a lateral or horizontal direction or both, being drawn into alignment with one another by the engagement, without binding or jamming of the posts in their respective bushings, by said pilot portion first entering said bore, said cone and truncated cone portions, and said land and valley portions acting as camming surfaces with respect to said sharp edge portion, to urge said plates in to proper registration.

2. A die set comprising two cooperating planar surface plates adapted to receive die members on complementary co-acting'surfaces thereof, a plurality of cylindrical guide posts fixed at substantially opposite edges in one of said plates, a plurality of mating bushings provided at substantially opposite edges in the other of said plates, each mating bushing having a bore, each of said guide posts removably engaging the bore of a mating bushing with close tolerance, the extension of the outer peripheral surface of the guide post and of the inner circumferential surface of the bushing defining a substantially common cylindrical surface, the said surface defining the projecting end of one of said post or bushing members being provided with a {pilot portion and a sharp edge portion, said pilot portion being provided with an inner and an outer end, said pilot portion being formed at the inner end with a first conical surface sloping in the direction of the outer end of said pilot portion, said'first conical-surface terminating at one end in an annular groove in said pilot portion, a second conical surface extending toward the outer end of said pilot portion and forming the other end of said groove and terminating in an annular land portion, said first conical surface being of alength greater than said second conical surface, said land portion terminating in a third conical surface extending toward the outer end of said pilot portion and terminating said pilot portion, said posts and bushings, upon simultaneous engagement and being misaligned in a lateral or horizontal direction or both, being drawn into alignment with one another by the engagement, without binding or jamming of the posts in their respective bushings, by said posts first entering said bores and said first, second and third conical surfaces and said land and said groove acting as camming surfaces with respect to said sharp edge portion to urge'said plates into proper registration.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Sindelar Oct. 28, 1924 Janiszewski May 6, 1930 5 Janiszewski Nov. 17, 1936 Lee Apr. 30, 1940 Danneman Apr. 27, 1943 6 Danneman June 22, 1943 Tauser Oct. 5, 1943 Burgess Apr. 18, 1950 Taylor May 18, 1954 OTHER REFERENCES Die Set Digest, v01. 1, N0. 3, 1956. 

